Production of vat dyestuffs



Patented Jan. 19, 1932 UNITED STATES PATENT OFFICE,

MAX ALBERT KUNZ, OF MANNHEIM, AJN D KARL KOBERLE, LUDWIGSHAFEN-ON-THE- RHINE, GERMANY, ASSIGNORS TO GENERAL ANILINE WORKS, INC., OF NEW YORK,

N. Y., A CORPORATION OF DELAWARE ERODUGTION OF VAT." DYESTUFFS No Drawing. Originalapplication filed June 16, 1827, Serial No. 199,420, and. in Germany August 9, 1926.

Divided and this application filed.

The subject matter of the present application has been divided out from our copending application for the manufacture of vat dyestuffs, Ser. No. 199,420, filed June 16,

; 1927 and relates to the manufacture of vat dyestuffs which are considered to be ms-anthradianthrones.

We have found that valuable vat dyestuffs C I! O 2.2-dimethy1-msms-anthradinaphthodianthrone anthrone.

The following examples will further illustrate the nature of the said invention which however is not restricted thereto. The parts are by weight.

40 Example 1 1 part of 2.2-dimethyl-ms-naphthodianthrone is introduced at 110 to 120 G. into a melt of 5 parts of caustic potash and 5 parts of ethyl alcohol. The temperature is raised July 28, 1928.

to from 17 0 to 175 C. and maintained at that temperature for another 6 hours, the melt being then dissolved in water. After the re- Serial No. 296,088.

' sulting dyestuff has been precipitated by an air blast, it is filtered by suction; the brown reaction product may be purified by treatment with hypochlorite solution. The dyestuif dissolves in concentrated sulfuric acid to a violet solution, and gives golden-yellow dyeings, fast to light and chlorine, on cotton from a blue-violet vat.

Example 2 1 part of 2.2-dimethyl-ms-naphthodianthrone is introduced at 210 G. into a melt of 10 parts of caustic potash, and after being f kept at from 220 to 230 C. for another two hours, the mass is treated as in Example 1. The resulting dyestuff is identical with that obtainable according to that example.

Example 3 Example 4 2.2 dimethyl ms naphthodianthrone is stirred and boiled in 10 parts of nitrobenzene, with addition of 4 parts of barium oxid, for about 4 hours. After filtration by suction, the resulting dyestuff is freed from admixed barium oxid by boiling with dilute hydrochloric acid; it is identical with the product obtained in Example 1.

What we claim is:

1. The process of producing new vat dyethen filtered by suction after cooling,

stufis which comprises subjecting a 2.2-dimethyl-ms-naphthodia nthrone to the action of an alkaline condensing agent.

2. The process of producing new vat dyestufis which comprises subjecting a 2.2'-dimethyl-ms-naphthodianthrone to the action of an alkaline condensing agent in a dilutin medium.

11 testimony whereof we afiix our signatures.

MAX ALBERT KUNZ. KARL KOBERLE. 

